The present invention relates to disposable absorbent articles such as, for example, diapers for infants or incontinent adults and relates more specifically to absorbent articles of simplified structure having seal elements at the crotch with an improved ability to contain lateral leaks.
Disposable absorbent articles such as diapers for infants or incontinent adults, designed to absorb and retain body fluids, are well known and generally consist of an upper layer of non-woven fabric permeable to liquids and designed to be in contact with the user's skin, an impermeable plastics sheet and an element of absorbent material, commonly known as a pad, between the two said layers.
One problem linked to the use of such absorbent articles is the containment of leakage at the crotch through the lateral edges which, in use, are positioned round the user's legs.
The use along the lateral edges of the absorbent article of elastic elements designed to provide, in use, a seal round the user's legs, has been known for some time, as shown in U.S. Pat. No. 3,860,003.
To improve the seal along the lateral edges, especially the containment of solid excrement which, by its nature, is not absorbed by the pad but tends to remain on the surface of the upper permeable layer, it has been proposed, as an alternative to or in combination with the conventional elastic elements along the lateral edges, to adopt elasticated flaps positioned inside the lateral edges of the absorbent article and either at the two sides of the pad or above it.
In use, the flaps are lifted from the surface of the absorbent article by the elastic elements incorporated in the said flaps, forming two longitudinal barriers able to guarantee better containment of lateral leakage.
For example, U.S. Pat. No. 4,704,116 describes a diaper of conventional structure with elasticated lateral edges and provided with two flaps positioned longitudinally, inwardly of these edges, above the pad, each flap in turn being delimited by two longitudinal edges and two ends.
Each flap is fixed to the upper layer of non-woven fabric along its outer longitudinal edge and at both ends, and is provided with at least one elastic element along the longitudinal edge facing the centre of the diaper.
The flaps are permeable to liquids and can either be formed by appropriately folding the upper non-woven fabric layer itself, or made separately and applied to the said upper layer.
This type of construction gives better protection against lateral leakage at the crotch but involves using more material to form the elasticated flaps.
In addition, as is commonly known in the art, if these flaps are to be impermeable to liquids, it is necessary for example that they be separately made of an impermeable material different from the material forming the upper permeable layer of the absorbent article; or, in the case of flaps made by folding the upper layer of non-woven fabric itself, it is necessary appropriately to treat the fabric or to add further impermeable elements.
A further development is presented in U.S. Pat. No. 4,808,177 which describes an absorbent article provided with the conventional elastics along the lateral edges to seal round the user's legs and with two so-called "floating" elasticated flaps positioned inwards of the said elasticated edges and characterized by a simplified structure.
In this patent each "floating" flap is made with an elastic element positioned longitudinally between the absorbent pad and the upper permeable non-woven fabric layer: the elastic element is fixed at both ends to the upper surface of the pad and to the lower surface of the non-woven fabric layer, while the intermediate portion remains unattached to the layers surrounding it.
In use the two elastic elements, contracting at the unattached intermediate portion, lift the upper layer at either side of the pad forming two longitudinal barriers.
Although this arrangement provides an absorbent article with simply constructed elasticated flaps, there is a need for an absorbent article with improved containment of lateral leakage characterised by impermeable elasticated flaps of simple structure whose manufacture does not involve a significantly larger use of raw material or the use of further treatment of materials compared to an absorbent article without elasticated flaps.